Production of chlorbutadiene



Patented Nov. 2, 1931 UNITED STATES PATENT OFFICE aoeaoss PRODUCTION orcrmoano'rsnmsn Ernst Eberhardt, Ludwigshaten-on-the-Bhine,

and Robert Stadler, Heidelberg, Germany, assignors to I. G.Farbenindnstrie Aktiengeselb' schait, Frankiort-on-the-Main, Germany NoDrawing. Application April 18, 1936, Serial No. 75,236. In Germany April27, 1935 5 Claims.

taining vinyl acetylene (which are obtainable for m example by leadingelectric-arc-acetylene over a solid catalyst containing a compound 01'monovalent copper) by leading the said gases together with theappropriate amount of hydrogen chloride at elevated temperature overactive car- 5 bon in the presence of halogen compounds of base metals ofthe 2nd or 4th group of the periodic system of the elements. Suitablehalogen compounds of the said kind are in particular halogen mercurycompounds, such as mercury or 20 mercurous chloride, bromide or iodide,and also for example lead chloride or cadmium chloride, zinc chlorideand stannous chloride. These metal halides may also be advantageouslyemployed in admixture with each other or with metallic mercury. Theactive carbon may also be charged with the said metals themselves, thechlorides of the metals then being formed during the reaction.

The reaction may be carried out at temperatures of between 50 and 200(3., preferably at between 100 and 150 C. The gases may be brought intoreaction in the dry state or in admixture with steam.

The formation of dichlorbutene may be sup 35 pressed to a great extentduring the process because the addition of hydrogen chloride may beaccurately regulated. Instead of gaseous hydrogen chloride, substanceswhich split of! hydrogen chloride, as for example phosgene to- 40 getherwith steam, may be employed.

Having regard to the known property of active carbon 01' exerting apolymerizing action on higher acetylenes, it is contrary to expectationthat the addition of hydrogen chloride should 45 proceed smoothlywithout any polymerization.

The following examples will further illustrate how the present inventionmay be carried out in practice, but the invention is not restricted tothese examples.

Example 1 A gas consisting mainly of hydrogen and containing about 10per cent oi. vinyl acetylene is led at a speed of 30 liters per hourtogether with 3 55 liters oi hydrogen chloride gas over 600 cubiccentimeters of active carbon which is laden wit calomel, the temperaturebeing 120 C. The gas mixture leaves the reaction chamber with a vinylacetylene content of about 3 per cent. In the course of 24 hours, 190grams of chlorbutadiene 5 (boiling point 60 0., density 0.956) and about5 grams of dichlorbutene are obtained. The unconverted vinyl acetyleneis condensed with the chlorbutadiene in cooled receivers and is returnedto the reaction chamber alter distilling it oil from the condensate.

Example 2 A gas mixture of the composition specified in Example 1 is ledtogether with hydrogen chloride gas in the manner described in Example 1over active carbon which has been laden with metallic mercury, thetemperature being 130 C. The gas leaves the reaction chamber with avinyl acetylene content of about 3 per cent. During the course of 24hours, 152 grams of chlorbutadiene and about 4 grams of dichlorbuteneare obtained.

Example 3 A gas mixture containing 10 per cent of vinyl 25 acetylene theremainder being mainly nitrogen is led together with hydrogen chlorideat a speed oi liters per hour at 100 C. over 600 cubic centimeters ofactive carbon which is laden with cadmium chloride. During the course of24' hours, 30 about 80 grams of liquid chlorbutadiene and from 2 to 3grams of products 01' higher boiling point are obtained.

Emmple 4 A gas mixture containing 8 per cent 01 vinyl acetylene, theremainder being hydrogen and methane, is led together with hydrogenchloride in a moist state and with .a speed of liters per hour at C.over 600 cubic centimeters oi active carbon which is laden with leadchloride. During the course of 24 hours, grams oi chlorbutadiene and 5grams of products of higher boiling point are obtained.

Example 5 45 action chamber has a vinyl acetylene content 01' about 1percent. Duringthecourseoi24hours,

150 grams of chloi-butadiene and about 2 grams of dichlorbutene areobtained.

.wmt we claim is:-- v 1. A process of producing chlorbutadiene fromgases containing vinyl acetylene which comprises leading the said gasestogether with the corresponding amount of hydrogen chloride at ele- 10vated temperature over active carbon in the presence of a halide of ametal selected from the group consisting oi base metals of the secondand fourth groups of the periodicsystem of the elements.

2. A process oi producing chlorbutadiene from gases containing vinylacetylene which comprises leading the said gases together with thecorresponding amount of hydrogen chloride over active carbon in thepresence of a halide of a metal 20 selected from the group consisting ofbase metals of the second and fourth groups of the periodic system ofthe elements at temperatures of betwen 50 C. and 200 C.

-3. A process of producing chlorbutadiene from 25 gases containing vinylacetylene which comprises leading the said gases together .withsubstances which yield hydrogen chloride under'the reaction conditionsat elevated temperature over active carbon in the presence of a halideo! a metal selected from the group consisting of base metals of thesecond and fourth groups oi. the periodic system of the elements.

5. A process of producing chlorbutadiene i'rom gases containing vinylacetylene which comprises leading the said gases together with thecorresponding amount of hydrogen chloride at elevated temperature overactive carbon in the pres ence of mercurous chloride.

ERNST EBERHARDT. ROBERT STADLER.

